Tool for concrete formwork



No'v. 10, 1936. T, THOMSEN 2,060,646

TOOL FOR CONCRETE FORMWORK Fild July .24, 1935 INVENTOR,

7. 5. Thomsen, 7

ATTORNEY.

Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE TOOL FOR CONCRETE romuwonx Thomas S. Thomson, Kansas City, Mo.

Application July 24, 1935, Serial No. 32,892

4 Claims. (Cl. 254-79) The present invention relates to tools for use in cement and concrete construction work, and

the primary object in view is to devise an 'eflicient hand-operated tool for the manipulation of the metal straps or bands which are employed for securing together the different parts of the formwork ordinarily required in such cement and concrete construction.

Accordingly I have devised an extremely sim- 10 ple and practical tool which is effective for such operations as are requiredof the workman for 25 parts with practically nothing to get out of order.

With the foregoing general objects in view, the invention will now be described by reference to the accompanying drawing illustrating a practical form of the improved tool, after which those features and combinations deemed to be novel 1 claimed. I y

In the draw n8- Figure 1 is a perspective view showing a portion of a formwork, and the improved tool also shown in operation for tightening a metal tie strap or band to be nailed upon said formwork;

Figure 2 is a horizontal sectional view, representing a section taken on the line '2-2 of Fig- 40 1; I

Figure 3 is a sinziil nview, but illustrating a different mode-of use oftthe improved tool;

a Figure 4 is an enlarged detail sectional view of the head portion of the tool; 45 Figure 5 is a sectional view,representing a section taken on the line 5-5 of Figure 4; and

Figure 6 is a perspective view similar to the a view shown in Figure 1, but showing the tool provided with an accessory device in the form of a 60 Drop or bracing attachment, for adjustably supporting the tool in certain of its operative positions while in use.

Referring now to the drawing in detail, the use of the improved tool is illustrated in connection 55 with the work for which it is most specially and patentable will be particularly set forth and adapted, i. e., in connection with the-application,

tightening and fastening of the metal tie straps or bands i required for fastening together the various frame members i2 used in constructing the formwork. The tool itself comprises a head-piece of tool steel, the opposite sides 14 of which are formed with spaced pointed terminals or prongs i5 which are provided with alined chisel edges I6 for form-engaging purposes. The opposite sides 10 14 of the head-piece are connected by a transverse element such as a block i8 formed with a threaded passage i9- for a screw-threaded rod 20-; the outer end of this rod is provided with a suitable operating handle 22, while its other end is pointed, as indicated at 24, for cooperation with a suitable opening 25 which is formed in another transverse element such as a connecting 1 plate or bar 21 also located between saidside portions H in spa'ced relation to the block I8 and presenting said opening 25 in alinement with the central point 24 of the rod 20.

. The spaced relationship of the block i8 and the plate or bar 21 also provides a passage 28 through which to thread the ends of the straps 25 or bands ill, to which the tool may then be securely clamped at any desired point by the operation of the. screw-threaded rod 20 for that purpose, as illustrated in Figures 1 to 3, which operation produces a punch-like action as the pointed 30 :end of said rod jams the metal of the band into the opening 25. Figures 1 and 2 illustrate the operation in relation .tothe formwork I! of a pillar or column; the tie straps or bands are naile'd (as indicated at 30) at one end and then,

being clamped within the head-piece of the tool as just described, may be drawn and tightened with a powerful pulling action by a prying oper-' ation of the tool, in the mannersillustrated.

This drawing and tightening operation is car- 40 ried out by jabbing the biting or. chisel edges ii of the prongs i5 into the. woodwork of the form structure and'then exerting a prying action by means'of the tool to whatever extent is necessary for producing the desiredstrap-tightening eflect, preparatory for the nailing of the remainder of the strap or band to the form. If any dimculty should be experienced in causing the chisel edges i6 to bite into the form (due, to hardness of the wood, for example), the work. man can deliver a hammer blow upon the outer end of the rod 20, or preferably'upon the blunt ends of 'the sides I! of the head-piece, for driving the prongs I 6 and thereby causing the said edges I. to pierce into the wood for eifectiveiy anchoring the tool.

A diiferent mode of connecting the tool with the strap ends may be employed, as illustrated in lfigure 3 in relation to the form structure-for a beam. In this case, the end of the strap or band III is threaded through the passage 28 from the opposite direction before being clamped by the pointed end of the rod 20. By this means a still more powerful drawing and tightening action may be exerted by the tool's lever action,- the strap being even more securely held, and the operating length or leverage of the tool being also greater, due to the strap passing beneath the bar 21 and between the prongs It. This may be found particularly desirable in connection with heavier work, using heavier ties or bands,

or in some cases a plurality of straps or bands my be used and fastened at one and the same time for purposes of greater strength, and stronger anchorage effect.

In Figure 6 the tool is illustrated as provided with an accessory or bracing attachment for facilitating the use of the tool in the manipulation and fastening of the straps or tie bands ill by a single operator or workman.

This accessory or attachment comprises a pair of links 32, II, pivotally connected at 34. The. outer end of the link 32 is provided with a yoke 32' pivotally connected at 35 to a collar 3 adapted to be slidingly mounted upon the screw rod III for movement toward or from a stop pin 31 which is fitted to said rod. The outer end of the link 33 is formed with a pair of prongs I! having alined chisel edges l8 similar to the prong construction already described as a part of the tool head-piece. The link a is also provided with a stop lug a for limiting the straightening movement of the links, and preferably the pivot ll is provided with a handle 3! for convenience in operating and adjusting the attachment; I

It will be apparent that with this accessory construction, on operating the tool for drawing up and tightening the strap, Ill, the attachment may be conveniently manipulated to brace the tool in the position into which it has been operated to hold the strap, and so hold the tool .in such position while the workman may have the' free use of both his hands for the work of punching and nailing the strap before it is released from the gripof the tool.

In both instances of the use of the chisel edges II and II, there is the decided advantage of effectively preventing any casual rotative tendency of the tool, so that the same maintains its position against any influence tending to swing it out of any given operative position. 7

It will therefore be seen that an extremely simple and yet eilicient form of tool and accessory or attachment have been devised for the carrying out of .the aforesaid obiects of my invention. The construction may of course be carried out to any size necessary for meeting the requirements of any special conditions, and for exerting any necessary mechanical effort re:- quired for the drawing up and tightening of the straps or bands. While the tool proper. as shown, may be handled and operated to a certain degree, in most of its operations, without the accessory or attachment, by means of a single worlnnan, the provision of said attachment facilitates in a marked manner the handling and operation of the tool by one workman by virtue of the bracingand supporting function provided by such bracing and holding attachment, and thus in a very great degree promotes the ease and convenience of the work of the operator, and to a like extent increases the utility of the device.

While I have herein described and illustrated what I have found to constitute a satisfactory and efllcient embodiment of the improvements comprising my invention, I desire to be understood as reserving the right to make whatever changes and modifications may be deemed to fairly fall within thescope of the appended claims.

What I claim is:

1. A tool for formwork, comprising a headpiece provided with spaced prongs formed with alined chisel edges, means providing a strap or band passage through said head-piece, and means for clamping said strap orband with a punching action within said passage, said last means including a rod forming a handle for producing a prying action upon the band or strap by a fulcruming movement of the tool upon said chisel edges.

2. A tool for formwork, comprising a headpiece provided with spaced prongs formed with alined chisel edges and also with spaced transverse elements providing a strap or band passage, one of said elementshaving an opening, and a rod threaded through the other transverse element in alinement with said opening for clamping the bands or straps with a punching action, said rod forming a handle for producing a prying action upon the band or strap by a fulcruming movement of the tool upon said chisel edges.

3. A tool for formwork, comprising a headpiece provided with spaced prongs formed with alined chisel edges and also with spaced transverse elements providing a strap or band passage, one of said elements having an opening.-

and an elongated rod threaded through said other element and formed with a pointed terminal for cooperation with said opening for clamping the bands with a punching action, said rod projecting beyond said head-piece and in alinement with said space between said prongs to provide a handle for producing a prying action upon the bands or straps by a fulcruming movement of the tool upon said chisel edges.

4. A tool for formwork, comprising a headpiece provided with spaced prongs for engagement with the formwork, means providing a strap or band passage through said head-piece, a rod operative for clamping the strap or band within said passage, a pair of toggle links forming a bracing attachment for holding the tool in strap-tightening position, one of said links having prong terminals for engagement with the formwork, and means for slidingly connecting the other of said links with said rod.

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